* SoftUART fixes:
- Simplify code by using lua_L* functions and using userdata properly
- Fix some edge-cases
- Add more examples to documentation
* Don't de-register interrupt hook if there is more RX instances
* More bug fixes and registering simplification with luaL_reref and unref2
* Correct documentation of SoftUART module
- Lots of minor but nasty bugfixes to get all tests to run clean
- core lua and test suite fixes to allow luac -F to run cleanly against test suite
- next tranch to get LFS working
- luac.cross -a options plus fixes from feedback
- UART fixes and lua.c merge
- commit of wip prior to rebaselining against current dev
- more tweaks